With over three-decades of combating the HIV epidemic, new HIV infections have decreased by 38% globally since 2001. Still, HIV is one of most serious health and developmental challenges for human beings, particularly for people living with HIV/AIDS (PLWH) in low- and middle-income countries (LMIC). HIV disclosure (self-disclosure of HIV seropositive status) is a critical step of HIV treatment and care continuum with potential benefits for both PLWH and society. Disclosure is a process of gradual (across different stages) and selective (with various targets) delivery of information embedded in social context and social relationships. There are various types of disclosure in practice depending on the natures of social relationships. In this application, HIV disclosure refers to a process in which PLWH disclose their HIV positive status to others including partners, children, family members, and significant others (i.e., general disclosure). Global literature suggests that disclosure may facilitate PLWH's actively coping with HIV/AIDS by enhancing social support, improving access to medical care, promoting medication adherence, increasing opportunities to discuss and implement HIV risk reduction, and reducing psychological stress. However, we have limited understanding on whether HIV disclosure will affect clinical outcomes (e.g., CD4 count, viral load, disease progression) among PLWH. There is also a dearth of empirical data regarding potential mechanisms underlying the effects of HIV disclosure on clinical outcomes, as well as intrapersonal, interpersonal, and social factors that may potentially moderate or mediate the effects of disclosure on clinical outcomes. Recent research, including our own preliminary data, has suggested two potential pathways: biological pathway (e.g., affecting the neuroendocrine and sympathetic nervous response to chronic stress) and behavioral pathway (e.g., affecting the behaviors that are crucial to medication adherence). The possible biological and behavioral mechanisms have been largely hypothesized, but not empirically tested in longitudinal studies. In addition, existing HIV disclosure research is mostly based on data through self-report or qualitative inquiries rather than objective biomedical measures. In the current application, we propose to examine long-term effects of HIV disclosure on clinical outcomes through a longitudinal cohort of 400 people recently diagnosed as HIV positive (i.e., people who have been diagnosed with HIV infection since January 2014) in Guangxi China where we have built a strong research infrastructure and community collaboration through NIH-funded research since 2004. The primary measures include HIV disclosure patterns characterized by disclosure stages, chronic stress, adherence to HIV treatment and care, and clinical outcomes (CD4 count, viral load, and disease progression). In addition to self-reported data (e.g., depression and anxiety, medication adherence), biomarkers of chronic stress (hair cortisol) and medication adherence (hair antiretroviral concentration) will be employed. The current application addresses the importance of investigating how positive psychosocial/behavioral factor (e.g., HIV disclosure) may get under the skin to influence physical health and thus broadens the research perspective in which we review the effects of HIV disclosure. It also expands existing conceptualization and methodology on HIV disclosure research by explicitly assessing two dynamic pathways of the effects of HIV disclosure on clinical outcomes with novel biomarkers. The proposed research is significant as it addresses a critical issue in HIV treatment and care. The empirical data and findings will contribute to our knowledge base and inform future HIV disclosure intervention efforts based on comprehensive data of the dynamic process of how disclosure influences physical health among PLWH.